This invention relates to heating cooking appliances equipped with a microcomputer for controlling a plurality of relays so that the heating cooking operation is executed, and more particularly to such heating cooking appliances in which the microcomputer is provided with a function of testing the relays.
A high frequency cooking apparatus or microwave oven is, for example, provided with a plurality of relays which are controlled by a microcomputer so that various kinds of cooking modes are executed The high frequency cooking apparatus of the multifunctional type is provided with five or more relays. Conventionally, a series circuit of a light-emitting diode and a resistance is connected in parallel with each relay in order that each relay is tested for normal operation Each light-emitting diode is adapted to be activated when each relay is operated for test.
In the above-described arrangement, however, the light-emitting diodes and resistances are needed in accordance with the number of relays. Further, the size of a printed wiring board is increased as the number of light-emitting diodes and resistances is increased, resulting in large increase of the production cost of the high frequency cooking apparatus Moreover, in testing the relays, a tester needs to directly view each light-emitting diode provided on the printed wiring board. Accordingly, cabinets need to be successively detached from the high frequency cooking apparatus in the case that the relays are tested in repair or inspection after assembling, which complicates the testing work Additionally, the light-emitting diode is activated even in the case that the corresponding relay coil has burned out.